</section>
<section remap="h4">
<title>Visualizing Results</title>
- <para>It is useful to import the <literal>obdfilter-survey</literal> script summary data (it
- is fixed width) into Excel (or any graphing package) and graph the bandwidth versus the
- number of threads for varying numbers of concurrent regions. This shows how the OSS
- performs for a given number of concurrently-accessed objects (files) with varying numbers
- of I/Os in flight.</para>
- <para>It is also useful to monitor and record average disk I/O sizes during each test using the 'disk io size' histogram in the file <literal>/proc/fs/lustre/obdfilter/</literal> (see <xref linkend="dbdoclet.50438271_55057"/> for details). These numbers help identify problems in the system when full-sized I/Os are not submitted to the underlying disk. This may be caused by problems in the device driver or Linux block layer.</para>
- <screen> */brw_stats</screen>
- <para>The <literal>plot-obdfilter</literal> script included in the I/O toolkit is an example of processing output files to a .csv format and plotting a graph using <literal>gnuplot</literal>.</para>
+ <para>It is useful to import the <literal>obdfilter-survey</literal>
+ script summary data (it is fixed width) into Excel (or any graphing
+ package) and graph the bandwidth versus the number of threads for
+ varying numbers of concurrent regions. This shows how the OSS performs
+ for a given number of concurrently-accessed objects (files) with varying
+ numbers of I/Os in flight.</para>
+ <para>It is also useful to monitor and record average disk I/O sizes
+ during each test using the 'disk io size' histogram in the
+ file <literal>/proc/fs/lustre/obdfilter/*/brw_stats</literal>
+ (see <xref linkend="dbdoclet.50438271_55057"/> for details). These
+ numbers help identify problems in the system when full-sized I/Os are
+ not submitted to the underlying disk. This may be caused by problems in
+ the device driver or Linux block layer.</para>
+ <para>The <literal>plot-obdfilter</literal> script included in the I/O
+ toolkit is an example of processing output files to a .csv format and
+ plotting a graph using <literal>gnuplot</literal>.</para>
</section>
</section>
</section>